1 update customers a -- 使用別名 2 set city_name=(select b.city_name from tmp_cust_city b where b.customer_id=a.customer_id) 3 where exists (select 1 4 from tmp_cust_city b 5 where b.customer_id=a.customer_id 6 ) 7 -- update 超過2個值 8 update customers a -- 使用別名 9 set (city_name,customer_type)=(select b.city_name,b.customer_type 10 from tmp_cust_city b 11 where b.customer_id=a.customer_id) 12 where exists (select 1 13 from tmp_cust_city b 14 where b.customer_id=a.customer_id 15 )